XXTi Posted August 27, 2007 Share Posted August 27, 2007 I went out to the shop to move the XX around and found that the front brake lever went to the handle bar. The bike's been sitting for a couple of weeks, but the brakes worked OK when I parked it. There is fluid in the reservoir, but the brakes won't even pump up. I'm guessing I have a problem with the master cylinder, but I won't be sure until I tear into the system. It looks like there's a kit available to rebuild the MC. Has anyone done it? Quote Link to comment Share on other sites More sharing options...
cbrbear Posted August 27, 2007 Share Posted August 27, 2007 I went out to the shop to move the XX around and found that the front brake lever went to the handle bar. The bike's been sitting for a couple of weeks, but the brakes worked OK when I parked it. There is fluid in the reservoir, but the brakes won't even pump up. I'm guessing I have a problem with the master cylinder, but I won't be sure until I tear into the system. It looks like there's a kit available to rebuild the MC. Has anyone done it? mc rebuilds are easy but that may not be the problem. remember the linked brakes and there could be other issues. does your rear brake pedal also go to the floor? Quote Link to comment Share on other sites More sharing options...
rodantking Posted August 27, 2007 Share Posted August 27, 2007 i believe the front brake lever only operates the outer front pistons and is indendent of the rear brake. Sounds like air in the line. Question is how did it get there. don't forget to check the lines and fitting also. I remember Dale (warchild) did a write up on mc's about 2 years ago on this board. Run a sceach and use his name to narrow the field. Quote Link to comment Share on other sites More sharing options...
cbrbear Posted August 27, 2007 Share Posted August 27, 2007 i believe the front brake lever only operates the outer front pistons and is indendent of the rear brake. Sounds like air in the line. Question is how did it get there. don't forget to check the lines and fitting also. I remember Dale (warchild) did a write up on mc's about 2 years ago on this board. Run a sceach and use his name to narrow the field. I am pretty sure the front brake operates the rear also and vice versa... not 100 percent sure but pretty sure both operate both, easy way to find out put it on the center stand and put it in first gear then operate front brake lever and see if the rear wheel slows or stops Quote Link to comment Share on other sites More sharing options...
R1000 Posted August 27, 2007 Share Posted August 27, 2007 i believe the front brake lever only operates the outer front pistons and is indendent of the rear brake. Sounds like air in the line. Question is how did it get there. don't forget to check the lines and fitting also. I remember Dale (warchild) did a write up on mc's about 2 years ago on this board. Run a sceach and use his name to narrow the field. I am pretty sure the front brake operates the rear also and vice versa... not 100 percent sure but pretty sure both operate both, easy way to find out put it on the center stand and put it in first gear then operate front brake lever and see if the rear wheel slows or stops The front brake hydraulic fluid has no direct connection to the rear brake. The left front calliper tilts forward when the brake is applied, if the front wheel turns. This put pressure on a piston to the secondary master cylinder that controls the rear brake system. Quote Link to comment Share on other sites More sharing options...
airborneXX Posted August 27, 2007 Share Posted August 27, 2007 +1 on what R1000 says. Inspect the front brake M/C, lines and front calipers. There is no direct hydraulic connection from the front brake to the rear. It sounds like a seal in the master cylinder has gone bad. Quote Link to comment Share on other sites More sharing options...
cbrbear Posted August 27, 2007 Share Posted August 27, 2007 thanks for the knowledge I delinked mine a long time ago and now have standard set up with only 3 lines, one to each caliper nothing else nothing connected between front and rear. Quote Link to comment Share on other sites More sharing options...
XXTi Posted August 27, 2007 Author Share Posted August 27, 2007 Thanks guys. I know how the brake system works. I just wondered if anyone had rebuilt a MC before. This is the first time I've heard about anyone having this problem. Quote Link to comment Share on other sites More sharing options...
Northman Posted August 28, 2007 Share Posted August 28, 2007 Thanks guys. I know how the brake system works. I just wondered if anyone had rebuilt a MC before. This is the first time I've heard about anyone having this problem. Pretty simple to do, Jim. Just disassemble, clean everything, replace the seals, and re-assemble with clean brake fluid as your assembly lube. If you screw it up, I can always send you mine Quote Link to comment Share on other sites More sharing options...
XXTi Posted August 28, 2007 Author Share Posted August 28, 2007 Thanks Chris. I have the parts on order and I'll let you know how it goes. Quote Link to comment Share on other sites More sharing options...
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